The semiconductor integrated circuit (IC) industry has experienced exponential growth over the last few decades. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased.
With the continuous decrease in feature size of integrated circuits, a flip chip package technology become more widespread because the flip chip package technology is applicable to very high density I/O connections and has high reliability in interconnects. However, the conventional flip chip package technology has not been entirely satisfactory in every aspect.